The solar radiation values have been composed by automatic weather station using the device that namely pyranometer. The device is functions to records all the radiation values that have been dispersed, and these data are very useful for it experimental works and solar device’s development. In addition, for modeling and designing on solar radiation system application is needed for complete data observation. Unfortunately, lack for obtained the complete solar radiation data frequently occur due to several technical problems, which mainly contributed by monitoring device. Into encountering this matter, estimation missing values in an effort to substitute absent values with imputedmore » data. This paper aimed to evaluate several piecewise interpolation techniques likes linear, splines, cubic, and nearest neighbor into dealing missing values in hourly solar radiation data. Then, proposed an extendable work into investigating the potential used of cubic Bezier technique and cubic Said-ball method as estimator tools. As result, methods for cubic Bezier and Said-ball perform the best compare to another piecewise imputation technique.« less

The use of satellite data to estimate solar irradiance at ground level represents a valid alternative to ground measurements of solar radiation. This paper continues the analysis and evaluation, started in a previous paper, of the best known methods for calculating solar irradiance at the earth's surface using geostationary satellite data. In the previous paper, the authors examined and compared the so-called statistical models. Now they will consider the physical models and point out the difference between them. Finally, a summary will be made for the assessments and comparisons carried out on the methods described.

The use of satellite data to estimate solar irradiance at ground level represents a valid alternative to ground measurements of solar radiation. The best known methods of estimating the solar irradiance at the earth's surface using geostationary satellite data are reviewed. The models may be classified into statistical and physical models, depending on the approach used to treat the interaction between solar radiation and atmosphere. The main hypotheses and algorithms used in four statistical models are extensively presented and discussed. The difference between these methods are pointed out. Physical models will be examined in a second paper. This second papermore » will include various assessments regarding the performances of the described methods and summaries of comparisons between the different models.« less

We compute the full disc irradiance at 2800 MHz ('F10.7') on the basis of individual active regions (ARs) on the sun as observed in the light of the Ca II K line at 393 nm. The solar radio emission is used as a stand-in for UV measurements from above the atmosphere, since it does not have significant calibration problems, and since day by day records are available for many years. We illustrate in detail the techniques for parametrization of the model calculations which, with few changes, are applicable to UV measurements. In addition to the excellent overall agreement and themore » impressively close correspondence of day to day variations, we find no indication of a systematic discrepancy between model and observations over the entire 10-year period. Nor do we find a contribution to the 2800 MHz irradiance that is not directly related to individual ARs on the sun at any given day. We believe that our analysis, by comparison with previous work, is much more detailed without being much more complex, and that it offers a serious chance for an independent evaluation of short-term as well as long-term fluctuations of the solar observed irradiance.« less

Satellite derived irradiance maps with a high temporal and spatial resolution are a valuable data source for the analysis of large scale grid integrated solar energy systems. For an appropriate use of this huge data base convenient methods for the characterization of the spatial and temporal structures of the satellite derived irradiance field are necessary. In this paper we introduce the application of a multiresolution decomposition for the structure analysis of irradiance maps. Using this tool the maps are decomposed into local averages (context) and gradients (detail) on various spatial scales. The information on the context and the detail maymore » be directly interpreted in terms that are of interest, e.g. for the analysis of PV-systems implemented on a very large scale. 20 refs., 14 figs.« less